Climate Change Costs Are Not Hitting the Plate

As the US was experiencing the 2012 drought, climate alarmists were quick to jump on the bandwagon -- making all sorts of climate change suggestions in the mainstream media absent any hard data. Now that the 2012 data is in, we can (and should) reconsider many of the claims made last summer.

One argument that was put forward by Thomas Homer-Dixon at the University of Waterloo involved "[c]limate change's costs hit[ting] the plate." In his article, Homer-Dixon makes reference to -- and links -- climate change with the 2012 U.S. drought, corn and soybean production, supposedly record high corn prices, and "imperiled food security." Of course, no data are provided in his article. When we examine the issue, we find the results are not favorable towards Homer-Dixon's point of view.

There has been no significant change in any of the three major annual drought indices (Palmer Drought Severity Index [PDSI], Palmer Hydrological Drought Index [PHDI], and Palmer Modified Drought Index [PMDI]) for the contiguous U.S. since records began in 1895. In the USA's corn and soybean belts, the annual and summertime PDSI, PHDI, and PMDI all exhibit trends towards reduced (not increasing) drought conditions over time.

There is no clear indication of any significant negative climate-change impacts on this dataset. The 2012 drought had a barely noticeable impact on the long-term increasing production trends for both of these crops, and we have seen much larger year-to-year variability in the past.

As well, there are no clear climate change-related trends in corn and soybean yields from the U.S. since records began (see figure below):

The effects of the 2012 drought on U.S. soybean yields was negligible from a historical perspective. While the 2012 corn yield declined by 16% from 2011, this was smaller than the yield reductions from 1994-95 (-18%), 1992-93 (-23%), 1987-88 (-29%), 1982-83 (-28%), 1946-47 (-23%), 1935-36 (-23%), 1933-34 (-18%), 1929-30 (-20%), 1923-24 (-21%), 1912-13 (-22%), 1900-1901 (-35%), 1891-92 (-17%), 1889-90 (-25%), 1880-81 (-27%), 1872-73 (-22%), and 1868-69 (-17%). The historical lesson is that there is occasionally large inter-annual variability in crop yields, and 2012 was by no means unique or part of a longer-term trend. Indeed, just a few weeks ago, the USDA predicted record-high corn and soybean crops for 2013.

Finally, what about the supposedly record-high corn prices? The following chart from the U.S. Department of Energy shows inflation-adjusted corn and soybean prices (in constant 2007 dollars) between 1886 and 2012.

The DOE makes the following statement: "This chart shows that, when corrected for inflation, both corn and soy prices are near all-time lows." This brings up a key point that Homer-Dixon should have considered -- unless you adjust your historical price data for inflation, any resulting year-to-year comparisons are effectively meaningless.

So much for "imperiled food security" because "[c]limate change's costs [are] hit[ting] the plate" and depressing U.S. food production.

As the US was experiencing the 2012 drought, climate alarmists were quick to jump on the bandwagon -- making all sorts of climate change suggestions in the mainstream media absent any hard data. Now that the 2012 data is in, we can (and should) reconsider many of the claims made last summer.

One argument that was put forward by Thomas Homer-Dixon at the University of Waterloo involved "[c]limate change's costs hit[ting] the plate." In his article, Homer-Dixon makes reference to -- and links -- climate change with the 2012 U.S. drought, corn and soybean production, supposedly record high corn prices, and "imperiled food security." Of course, no data are provided in his article. When we examine the issue, we find the results are not favorable towards Homer-Dixon's point of view.

There has been no significant change in any of the three major annual drought indices (Palmer Drought Severity Index [PDSI], Palmer Hydrological Drought Index [PHDI], and Palmer Modified Drought Index [PMDI]) for the contiguous U.S. since records began in 1895. In the USA's corn and soybean belts, the annual and summertime PDSI, PHDI, and PMDI all exhibit trends towards reduced (not increasing) drought conditions over time.

There is no clear indication of any significant negative climate-change impacts on this dataset. The 2012 drought had a barely noticeable impact on the long-term increasing production trends for both of these crops, and we have seen much larger year-to-year variability in the past.

As well, there are no clear climate change-related trends in corn and soybean yields from the U.S. since records began (see figure below):

The effects of the 2012 drought on U.S. soybean yields was negligible from a historical perspective. While the 2012 corn yield declined by 16% from 2011, this was smaller than the yield reductions from 1994-95 (-18%), 1992-93 (-23%), 1987-88 (-29%), 1982-83 (-28%), 1946-47 (-23%), 1935-36 (-23%), 1933-34 (-18%), 1929-30 (-20%), 1923-24 (-21%), 1912-13 (-22%), 1900-1901 (-35%), 1891-92 (-17%), 1889-90 (-25%), 1880-81 (-27%), 1872-73 (-22%), and 1868-69 (-17%). The historical lesson is that there is occasionally large inter-annual variability in crop yields, and 2012 was by no means unique or part of a longer-term trend. Indeed, just a few weeks ago, the USDA predicted record-high corn and soybean crops for 2013.

Finally, what about the supposedly record-high corn prices? The following chart from the U.S. Department of Energy shows inflation-adjusted corn and soybean prices (in constant 2007 dollars) between 1886 and 2012.

The DOE makes the following statement: "This chart shows that, when corrected for inflation, both corn and soy prices are near all-time lows." This brings up a key point that Homer-Dixon should have considered -- unless you adjust your historical price data for inflation, any resulting year-to-year comparisons are effectively meaningless.

So much for "imperiled food security" because "[c]limate change's costs [are] hit[ting] the plate" and depressing U.S. food production.